A case of immunocompetent intracranial cryptococcoma in which intraoperative rapid pathological diagnosis and polymerase chain reaction led to early treatment: What to know to avoid misdiagnosis as brain tumor

Abstract

Background: Cryptococcal infections of the central nervous system are infrequent in immunocompetent hosts and usually present as meningitis. However, a fungal mass called a cryptococcoma may form, requiring caution in therapeutic intervention. Here, we report a rare case in which treatment of intraventricular cryptococcoma in an immunocompetent patient was facilitated by rapid pathological diagnosis. Case Description: A 58-year-old previously healthy man was admitted to our hospital with fever, headache, and gradually worsening hearing loss over 1 month. Cerebrospinal fluid analysis showed moderately elevated levels of protein and lymphocytic cells and decreased glucose. In addition, β2-microglobulin was highly elevated. Magnetic resonance imaging showed homogeneously enhanced lesions in lateral ventricles of the left and right hemispheres and the subarachnoid space, and 18F-fluorodeoxyglucose positron emission tomography revealed abnormal uptake corresponding to the lesion. A surgical excision was performed to achieve a definitive diagnosis. Intraoperative rapid pathology, including immunohistochemistry (IHC), yielded negative results for malignant tumor, suggesting the possibility of inflammatory granuloma. Additional targeted pathological diagnosis was immediately performed. Paraffin-embedded histopathological examination showed fibrocaseous granuloma and numerous fungal spores. Cryptococcus neoformans within the granuloma were suggested by Fontana–Masson and Grocott staining and confirmed by polymerase chain reaction (PCR), leading to a diagnosis of cryptococcoma. Antifungal agents were started 3 days postoperatively. The patient has since been doing well, with no recurrence. Conclusion: This pathology can be difficult to distinguish from a brain tumor, so early pathological diagnosis, including rapid pathology with IHC and PCR, may be crucial.